I'm sure this is stupid, but .....................

[speckled trout]

couldn't you reduce the temperature of your tank's water by simply making a "radiator" out of pvc pipe that siphons downward through a maze of pipe and is returned to the tank by a large in-line pump.

The water would intially be pulled downward by the suction of an in-line pump and returned by another strong pump.

All of this would be cooled by a fan pushing cool air through the maze of pipes before it is returned to the tank.

I just couldn't resist asking this question. If it's completely stupid, don't kill me!:uzi: :lol:

[RichConley]

Yes, it would cool the tank, but you'd have to find a metal suitable to exposure to saltwater, which pretty much limits you to expensive Ti, or high grade stainless.

THe pumps you use to run this loop would most likely produce more heat than the loops removed.

[istio]

A few people here have made evaporative coolers using computer or small extraction fans. Here's an eonomical solution if this is what you are after

http://www.reefcentral.com/forums/printthread.php?threadid=617581&perpage=62

[douggiestyle]

it will work. its more a question of "at what capacity". for this type of set work efficiantly (like a car radiator) you would need a large difference between the tank temp and the surrounding air temp. this is called delta T. for our purposes DT = room temp - tank temp.
"Newton's law of cooling, states that the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings. This form of heat loss principle, however, is not very precise.[for us precise enough]"quoted from wikopedia.

so its "your beer will get cold faster in the freezer than the frig"

the "radiator" would then need to be very large or very heat conductive or a combination of the two if the delta T was small. so in most all cases its not a viable solution.

[speckled trout]

I realize that plastic doesn't absorb heat very well. Is that the reason your saying you would need metal, so that the heat in the water could be conducted and then "released" to the the air as it travelled through the pipe, thus cooling the water?

Also, doesn't the length of tubing have to be taken into account when determining the amount of heat that will be released from the water as it travels through the pipe. The more pipe(surface area) the more heat it would release, right?

Also, since the water would be flowing downhill, once it leaves the tank, it wouldn't take that strong of a pump to siphon it downward. The job of the return pump wouldn't be to return it the heighth of the tank. The maze of pipes would have to be so that the water is essentially just being pulled down by gravity.

Like I said, it's probably stupid and won't work. :hmm4: :hammer:

[Paul B]

I think if you used PVC pipe you would need about 100 feet of it to do anything. Plastic is too good an insulator. Years ago I was thinking about using about 100' of PVC sprinkler tubing and burying it underground just like a sprinkler system. I decided not to do it because it is my belief that that much PVC would add too much plasticers to the water, that is the chemical in plactic that makes it flexable. I had no way of knowing the toxisity of it. In the future I may try it.
Paul

[loves saltwater]

Last but not least pushing water through a pipe causes heat thru the friction the heat is minimal but it will compound the cooling issue.

[speckled trout]

100' OF PVC wouldn't be that hard to fit under a stand if you did it right. For instance, if you basically followed a rectangular pattern and slightly angled each progressing rectangle downward it would only take 10 rectangle assuming each rectangle would be 10' all the way around it.

By the way, 100' of what diameter pipe where you referring to?

Also, a fan could be used to push air that is the same temperature as the rest of the room through the pipes. Wouldn't that essenetially make the pipes the same temperature as the room? Or, would the pipes be more or less the same temperature as the water being siphoned from the main tank? Oh well.......it 's just a stupid thought:confused: :fun5:

[Paul B]

I am talikng about 3/4" PVC. It would only work if it is burried in the damp ground where it is cooler. A fan would do nothing to cool water in PVC pipe. Of course that is only my opinion.
Paul

[Cuervo]

You also have to keep in mind that if you cram a radiator that big into a small space (under a stand) that it won't take long until you have heated the space, thus lowering your DeltaT, which removes your ability to transfer heat.

Think of the car radiator. It's relatively small, but there is a big difference between the water temp, and the air temp. In addition to that, there is ALOT of airflow through the radiator. If that radiator were kept in a small space, it would quickly become inefficient. Just look at how many cars overheat when they get stuck in traffic, and airflow gets limited.

There are people who do what you are talking about. It's called GeoThermal cooling. They basically bury alot of tubing several feet in the ground, where the earth temp is fairly constant.

The next thing to consider is cost factor. Suppose you did make a nice radiator and had some fans blowing through it. That's going to essentially remove heat from the tank and transfer it to your air. Then you will have to remove the heat from the air. Depending on where you live, this might be expensive from season to season.

My guess is that a small chiller would be more cost effective than going the route of a radiator.

[blakeoe]

I have heard of people using Mini fridge/freezers. drill a hole in each side of the freezer part. run a pipe in that connects to a coil of tubing (as big as you can fit) and out the other side to a pump that sends it back to the tank or sump. then you still have the fridge part for all your supplements and/or beverage of choice

[douggiestyle]

<a href=showthread.php?s=&postid=8497628#post8497628 target=_blank>Originally posted</a> by speckled trout
100' OF PVC wouldn't be that hard to fit under a stand if you did it right. For instance, if you basically followed a rectangular pattern and slightly angled each progressing rectangle downward it would only take 10 rectangle assuming each rectangle would be 10' all the way around it.

By the way, 100' of what diameter pipe where you referring to?

Also, a fan could be used to push air that is the same temperature as the rest of the room through the pipes. Wouldn't that essenetially make the pipes the same temperature as the room? Or, would the pipes be more or less the same temperature as the water being siphoned from the main tank? Oh well.......it 's just a stupid thought:confused: :fun5:

they would more or less be something in between.

those questions though go beyond the scope of newtons law. so now your into Fourier's law. and for that i will refer you to this

"the time rate of heat flow Q through a slab is proportional to the gradient of temperature difference:

DQ/Dt=kA(DT/Dx)

Q is the time rate of heat flow through a slab,
Dt is the change in time,
k is a conductivity constant (dependent on the nature of the material and its temperature),
A is the transversal surface area,
DT is the temperature difference through which the heat is being transferred,
Dx is the thickness of the body of matter through which the heat is passing.

This law forms the basis for the derivation of the heat equation." from wikopedia

so you need the conductivity, the thicknes and surface area to figure how much heat will be tranfered over what time limit.

basicly what i put in my earlier post.

the "radiator" would then need to be very large or very heat conductive or a combination of the two if the delta T was small. so in most all cases its not a viable solution.

"at what capacity", this will tell you if it is a viable solution.

[speckled trout]

What would the tubing be made of if you run it through a small frig?

[douggiestyle]

<a href=showthread.php?s=&postid=8498154#post8498154 target=_blank>Originally posted</a> by speckled trout
What would the tubing be made of if you run it through a small frig?

this is another idea that will work but to "what capacity"

ive done it and it does work. my experiance is; the tank was ten gallons, i had 50' of garden hose, a 4 cuft manual defrost frig with small freezer and a small power head. the tank was maintained at apx 20f below room temp.

[Paul B]

I used to have an Urchin collecting business and i would keep them at about 45 degrees. I built a chiller out of a discarded office water cooler. I got copper tubing (oh no, he's crazy) and coated it with fiberglass resin. I put the tubing on the bottom of the urchin tank and ran it to the sump of the water cooler which was filled with water. There was a small water pump in the sump of the cooler that circulated the water through the tubing in the urchin tank.
Urchins are much more sensitive to copper than fish but if I were to use it on a "real" fish and invert tank I would use titanium tubing.
Paul

[douggiestyle]

<a href=showthread.php?s=&postid=8498694#post8498694 target=_blank>Originally posted</a> by Paul B
I used to have an Urchin collecting business and i would keep them at about 45 degrees. I built a chiller out of a discarded office water cooler. I got copper tubing (oh no, he's crazy) and coated it with fiberglass resin. I put the tubing on the bottom of the urchin tank and ran it to the sump of the water cooler which was filled with water. There was a small water pump in the sump of the cooler that circulated the water through the tubing in the urchin tank.
Urchins are much more sensitive to copper than fish but if I were to use it on a "real" fish and invert tank I would use titanium tubing.
Paul

maybe thats why all my urchins died :lol:

[Paul B]

I hope I diden't sell them to you :lol: